The right option is; C. rod
Bacteria are unicellular, prokaryotic (cells with no true nucleus) microorganisms. Bacteria have various shape, size and structure. The three major shapes are; the sphere (coccus), the rod (bacillus) and the spiral (vibrio). The rod is the most common bacterial shape. Examples of rod shaped bacteria include; Bacillus cereus, Corynebacterium diphtheria and Coxiella burnetii.